Personal care products, such as diapers, sanitary napkins, adult incontinence garments, and the like are generally constructed from a number of different components and materials. Such articles usually have some portion, usually the backing layer constructed of a liquid repellent film material. The liquid repellent film commonly used includes plastic materials such as a polyethylene film or copolymers of ethylene and other polar and nonpolar monomers. The purpose of the liquid repellent layer is to minimize or prevent absorbed liquid that may, during use, exude from the absorbent and soil the user or adjacent clothing. The liquid repellent film also has the advantage of allowing greater utilization of the absorbent capacity of the product.
Although such products are relatively inexpensive, sanitary and easy to use, disposal of a soiled product is not without its problems. Typically, the soiled products are disposed in a solid waste receptacle. This adds to solid waste disposal costs and presents health risks to persons who may come in contact with the soiled product. An ideal disposal alternative would be to use municipal sewage treatment and private residential septic systems by flushing the soiled product in a toilet. Products suited for disposal in sewage systems are termed "flushable." While flushing such articles would be convenient, the liquid repellent material normally does not disintegrate in water. This tends to plug toilets and sewer pipes, frequently necessitating a visit from the plumber. At the municipal sewage treatment plant the liquid repellent material may disrupt operations by plugging screens and causing sewage disposal problems. It therefore becomes necessary, although undesirable, to separate the barrier film material from the absorbent article prior to flushing.
In addition to the article itself, typically the packaging in which the disposable article is distributed is also made from a water resistant material. Water resistivity is necessary to prevent the degradation of the packaging from environmental conditions and to protect the disposable articles therein. Although this packaging may be safely stored with other refuse for commercial disposal, and especially in the case of individual packaging of the products, it is often more convenient to dispose of the packaging in the toilet with the discarded disposable article. However, where such packaging is composed of a water resistant material, the aforementioned problems persist.
In an effort to overcome these deficiencies hydrophilic materials can be made, to a degree, hydrophobic. To make a hydrophilic material partially hydrophobic the material has to be treated with a hydrophobic material to impart the desired water resistant properties to the material. The problem with this method is that the material used to impart water repellency to the hydrophilic material may further interfere with the disintegration of the film when flushed, negating any advantage of using a hydrophilic material.
Alternatively, a hydrophobic material can be made, to a degree, hydrophilic. This typically has been achieved by modifying a water resistant material, such as polyethylene, with a hydrophilic monomer such as (meth)acrylic acids, (meth)acrylate esters, hydroxyalkyl (meth)acrylate, polyethylene glycol, and glycidal methacrylate thereby making a hydrophobic material more hydrophilic.
One consideration when modifying the hydrophobic property of the barrier film by blending a hydrophobic polymer with a hydrophilic polymer, is the compatibility of the two polymers. If the two polymers are completely non-compatible then the blended polymers may form films or other articles having poor mechanical and aesthetic compatibilities. Generally, blends of polyolefin with poly(ethylene oxide) are very poor.